Development of a Unifying Framework for Modeling Multi-component Diffusion in Polymer Solutions

In this work a unifying framework for modeling multi-component diffusion in mixed solvent polymer solutions is developed by introducing additional restrictions such as the Onsager reciprocal relations (ORR) and the quasi-equilibrium postulate. More specifically, three different multi-component diffusion models, namely the Zielinski and Hanley model, the Dabral et al. theory and the Alsoy–Duda model are revised by using the above restrictions which are based on sound principles of non-equilibrium thermodynamics. Realistic simulations for the solvent(s) evaporation from the water/acetone/cellulose acetate (CA) and formamide/acetone/CA systems were obtained by combining the above multi-component diffusion models with the ORR and the quasi-equilibrium postulate. It is believed that the results of this work could be used to further study diffusion in multi-component systems appearing in coating and membrane formation.